yes it is essential that you first become agriculturist - farmer and than you will be able to purchase agriculture land, the lands which you are going to purchase is NA land and that case it is not essential. After mutation your in Village Form No. VII/XII, take evidences of your being a farmer and with those evidences the land being purchased (agriculture) shall be mutatedin your name otherwise Tehsildar has powers to reject your Sale Deed and ultimately you have cancell it.
For mutation of your name in Village Form No. VII/XII there is prescribed form that you fill and along with evidences required under same you submit to reveue office of your area of land and they revenue authority shall call yuou upon along with all heirs of your deceased father and names of all family members who are entilte for share in land shall be mutated after due procedure and submission of Affidavit and panchnama requires to be signed by reevenue authority with photo identity and other documents then your name/s will be entered into revenue records and in V. F. No. VII/XII.